Emulsion polymerization of vinylidene compounds in the presence of hydrazine-alkylenepolyamine compositions



Patented Aug. 12, 1952 UNITED STATES PATENT OFFICE EMULSION POLYMERIZATION OF VINYL- IDENE COMPOUNDS IN THE PRESENCE OF HYDRAZINE-ALKYLENEPOLYAIVHN E COM- PO SITION S William B. Reynolds, John E. Wicklatz, and

Thomas J. Kennedy, Bartlesville, kla., assignors to Phillips Petroleum Company, a corporation of Delaware No Drawing. Application June 15, 1950,

Serial No. 168,374

' olefins. This application is a continuation-inpart of our copending application Serial No. 107,638, filed July 29, 1949.

With the increasing interest in low temperature emulsion polymerization, many variations in recipes and procedure have been developed in the interest of economy and efficiency in addition to the attention given to producing polymeric materials havingthe desired characteristics. Recipes of the redox type, that is, formulations wherein both oxidizing and reducing components. are present, have been widely used. Oxidizing components frequently employed include materials of a peroxidic nature, and particularly compounds such as benzoyl peroxide and cumene hydroperoxide. Even though any peroxidic material might be expected to function in the capacity of the oxidant in a redox emulsion polymerization system, that is not necessarily the case since in some instances little, if any, polymerization occurs while in other cases with different peroxides the reaction takes place at a satisfactory rate. Some peroxides may function fairly satisfactorily at higher temperatures but are of little value when it is desired to carry out polymerizations at low temperatures, say below the freezing point of water.

We have now discovered that excellent polymerization rates are obtained when liquid vinylidene compounds, polymerizable when dispersed in an aqueous medium, are dispersed in an aqueous medium and polymerized in the presence of a polymerization catalyst composition comprising an organic peroxide as an oxidant and a reductant, or activator, composition which comprises a mixture of hydrazine and an alkylenepolyamine. In general, when the reductant compositions used in the process of this invention are employed, polymerization occurs at a more rapid rate than when either hydrazine or the alkylenepolyamine is used by itself. The combination of the two, as a reductant composition, therefore seems to have a synergistic effect. This invention is of particular interest when it is desired to use amine compounds of low molecular Weight, such a ethylenediamine, diethylenetriamine, and

the like, since these compounds are regarded in many instances as possessing less activity in poly- 11 Claims. (c1. 26084.7)

merization, reactions than higher molecular weight compounds such as tetraethylenepentamine, pentamethylenehexamine, etc. Reactions, in general, are more sluggish at low temperatures than-at higher temperatures and polymerization reactions are noexception. It is' known that highly activated recipes are essential for reactions of this type. The reductant compositions used in the process of this invention are therefore especially adaptable for use in low temperature emulsion polymerization processes. In addition to the foregoing advantages, these recipes afford a means for effecting polymerization reactions in the absence of heavy metal salt activators.

An object of this invention is to polymerize unsaturated organic compounds.

Another object of this invention is to produce synthetic rubber.

A further object of thisinvention is to polymerize a monomeric material comprising a con jugated diene while dispersed in an aqueous medium.

Still another object of this invention is to effect, rapid polymerization at low polymerization temperatures of monomeric materials dispersed in aqueous media.

Further objects and advantage of this invention will become apparent, to one skilled in the art, from the accompanying disclosure and discussion.

The reductant, or activator, compositions used in the process of this invention comprise hydrazine and an alkylenepolyamine, such as ethylenediamine, diethylenetriamine, 2-methyl-3-azapentane 1,5 diamine, N 2(hydroxyethyl) 1,2- ethanediamine, N phenylethylenediamine, N- cyclohexyl N (2 aminoethyl)-1,2-ethanediamine, tetraethylenepentamine, N(2 hydroxytertiary-butyl) 1,2-propylenediamine, and the like. These alkylenepolyamines have the general formula RNH(CHXCHXNH) mC-HXCHXNI-h where R contains not more than eight carbon atoms and is of the group consisting of hydrogen, aliphatic, cycloaliphatic, aromatic, olefinic, and cycloolefinic radicals, each X contains not more than three carbon atoms and is of the group consisting of hydrogen and. aliphatic radicals, and m is an integer between 0 and 8, inclusive. Each of the foregoing radicals (other than hydrogen) can be completely hydrocarbon in character, and'R can be of mixed character when containing six or more carbon atoms, such as alkylcycloalkyl, aralkyl, alkaryl groups, and the like, and can also have non-hydrocarbon substituents, some of (tertiary which will have the effect of making them more water-soluble and less oil (hydrocarbon) -soluble; particularly useful non-hydrocarbon substituents include oxygen in the form of 'hydroxy and ether compounds, sulfur in similar compounds (i. e., mercapto compounds and thioethers) and halogen compounds. These hydrazine-alkylenepolyamine compositions appear to actas reductants and/or activators in the polymerization mixture, and no other activating ingredients,-such-as-compounds of polyvalent-multivalent metals, need be added in order to obtain satisfactory and rapid polymerization of the monomeric gmaterial. except as such compounds may fortuitously be present in the polymerization mixture. Similarly, no other reducing ingredient, such as a reducing sugar, need be added.

The organic peroxide used as the oxidant component of the polymerization catalyst shouldhave solubility properties such that the major portion of it is present in the liquid monomer phase,

" rather than in the aqueous medium,-under the polymerization conditions. Ingeneral,-twc groups "of organic peroxides can be used, those having the iormulaR'OOI-I; known as hydroperoxide or hydroperoxymethanes, and those having I the formula ROOR, where -R in each 'instance "is an =organic radical. These two groups are not-equivalents; however, and the hydroperoxides are'pre- -i5erred. The preferred hydroperoxides can 'be represented by the formula RR'R'COOH-Where- R is selected from the group consisting ofhydrogen and organic radicals, and each of -R- and R' is an organic radicaLor RR" together comprise a tetrameth'ylene'orpentamethylene group forming with the B -(Foch a cyclopentyle .or cycloheXylh-ydroperoxide. Each of RyRxand 'R" can be completely hydrocarbon in character; and can beof mixed character, such as aralkyl, alkaryl, and the like, and can also .have non-hydrocarbon substituents, some of which Willhavethejeffect. of. making them more Water-soluble. and less foil. (hydrocarbon). .solub1e;

particularly useful non-hydrocarbon substituents include oxygen in the form of hydroxyand ether compounds, sulfur. in. simlar compounds .(i; e. mercapto compounds-and thioethers),.and halogen compounds. Examples of such hydroper- .oxides include diisopropyl hydroperoxide (iso- (isopropy1p-henyl) hydroperoxymethane) methylethyl(ethoxy.phenyl) hydroperoxymethane, methyldecyl(methylphenyl) hydroperoxymethane, di-

methyldecylhydroperoxymethane, m'ethylohlorophenylphenylhydroperoxymethane, .and tertiarybutylisopropylbenzene hydroperoxide -(dimethylbutylphenylhydroperoxymethane) Such-,hydroperoxides can be easily preparedlby simple oxidation, with free oxygen, of .the corresponding hydrocarbon. or hydrocarbon derivative, 1. e; of the. parent .trisubstituted methane. The compounds to be oxidized is placed in a reactor,

heated to the desired temperature, and oxygen introduced at a controlled rate throughout. the

'reactionperiod. The-mixture is agitated during the reaction which-is generally allowed to continue from about one to ten hours. The tempera- "that is, ateither higher or vlower.temperatures.

.At the conclusion of the reaction" the oxidized mixture may be employed as such, that is, as a solution of the hydroperoxide composition in the parent compound, or unreacted compound may be stripped and the residual material employed.

TheQmaj'or:activeiingredient in such a composition isithejmonohydroperoxide, or a mixture of monchydroperoxides. This hydroperoxide group 'appears to result from introduction of two oxygen atomsc'b'etweenthe carbon atom of the trisubstituted-methane and the single hydrogen atom attached thereto. Where there is another similar jgrouping in. the molecule, the usual method of production just outlined appears to produce only the, monohydroperoxide even though a dihydroperoxide appears to be structurally possible. Thus, in a simple case, from such anoxidation 50f "diisopropylbenzene the primary product. appears to be:dimethyl('isopropylphenyl') hydroperoxymethane.

One large-group of these hydroperoxymethanes is that'group 'll'l WhiCh each of. the. three. substituent groups is a hydrocarbon radical. 1 One of the subgroups ofthese compounds is-thealkaryl- -dialkyl hydroperoxymethanes, in which .the .two

alkyl groups arerclatively 'short,.i.. ephavef-rom one to three or four carbon atoms each,.including dimethyhtertiary butylphenyl)hydroperoxymethane, dimethyhdiisopropylphenyl) hydrope'roxymethane, dimethyl(isoprop'ylphenyllhydroperoxymethane, idim'ethyl dodecylphenyl) hydroperoxymethane, dimethyl (methylphenyl hydroperoxymethaneyand corresponding methylethyl and diethyl compounds, and thefllike. .Another subgroup includes at least one longalkylgroup directly-attached to the hydroperoxymethane,

such as methyldecyl't nethylphenyl) hydroperoxy- "methane, ethyldecylphenylhydroperoxymethane,

and the like. Stillpanother subgroup. includes trialkyl compounds, such as .dimethyldecylhydroperoxymethane; and the like aralkyl compounds,

- such as l phenyl drmethyl-3ehydroperoxybutane,

can also be-considered .to .be -members.; ofQ-this group. -A further-subgroup includes .alkyldiaryl compounds; such as vmethyldiphenylhydroperoxy- -methane, -methylphenyltolylhydroproxymethane, and the like. "Afurther subgroup; is the. Miami compounds; such' as triphenylhydroperoxymethane, tritolylhydroperoxymethane,..and .the like. A furthersubgroup comprises cyclopentyland cyclohexyl hydroperoxides, such as result from oxidation of cyclohexane, methylcyclopentane, and phenylcyclohexane, and compounds contain- 7 ing condensed ring. structures such. as l,2,3,4,4a,,-

-9,10;10a-octahydrophenanthrene, which forms theoorresponding hydroperoxide upon oxidation, etc. 'These organic peroxides andhydroperoxides preferably willhave a total .of .not more than thirty carbon atomspermolecule, and the most active hydroperoxides usuallyhave at least ten totwelve carbonatomsper molecule. -Mixtures :of these peroxidesand/orhydroperoxides can be material, usingin eachinstance the-same units of .weight throughout, i. when the monomeric material is measured in pounds the hydroperoxide is measured in millipound mols. The same is true for other ingredients in the polymerization recipe. An optimum rate of polymerization is usually obtained with the amount of hydroperoxymethane between 0.1 and. millimols per 100 parts by weight of monomeric material.

The amount of alkylenepolyamine used to obtain optimum results will usually be in the range from 0.02 to 5 parts by weight per 100 parts of monomeric material, with 0.04 to 2 parts being most generally preferred. The ratio of hydrazine to polyamine is usually expressed 'inmols, 0.3 to 5 mols hydrazine being employed per 1 mol of amine.

The monomeric material polymerized to produce polymers by the processof this invention comprises unsaturated organic compounds which generally contain the characteristic structure CH2=C and, in most case's,'have at least one of the disconnected valencies attached to an electronegative group, that is, a grou which increases the polar character of 'the'frnolecule such as a chlorine group or an organic group contain: ing a double or triple bond such as vinyl; phenyl, cyano, carboxy or the like. Includediin this class of monomers are the conjugated butadienes or 1,3-butadienes such as butadiene (1,3-butadiene), 2,3rdimethyl-1,3-butadiene, isoprene, piperylene, 3-furyl-l,3- butadiene,l 3-methoxy-'l,3-butadiene and the like; haloprenes, such as chloroprene (2- chloro-1,3-butadiene), bromoprene, methylchloroprene (Z-chloro-S methyl-1,3-butadiene), and the like; aryl olefins such as styrene, variousalkyl styrenes, p chlorostyrene, p methoxystyrene, alpha methylstyrene, vinylnaphthalene and similar derivatives thereof, and the like; acrylic and substituted acrylic acids and their esters, nitriles and amides such a acrylic'acid, methacrylic acid, methyl acrylate, ethyl acrylate, methyl alpha-chloro-acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, methyl ethacrylate, acrylonitrile, methacrylonitrile, methacrylamide and the like, methyl isopropenyl ketone, methyl vinyl ketone, methyl vinyl ether, vinylethinyl alkyl carbinols, vinyl acetate, vinyl chloride, vinylidene chloride, vinylfurane, vinylcarbazole, vinylacetylene and other unsaturated hydrocarbons, esters, alcohols, acids,'ethers, etc.,

of the types described. Such unsaturated compounds may be polymerized alone, in which case simple linear polymers are formed, or mixtures of two or more of such compounds which are copolymerizable with each other in aqueous emulsion may be polymerized to form linear copolymers.

The present invention is directed primarily to the production of polymers, of conjugated dienes, which have physical properties classifying'theni' as synthetic rubber, and the invention 'is'parucu: larly applicable to the polymerization of'hydro-'- carbon monomeric materials. Such materials include 1,3-butadiene and other conjugate'ddiolefin hydrocarbons having not more than. six carbon atoms per molecule, halogen derivatives, such as chloroprene, fluoroprene, and the like,, either alone, in admixture with each other, or together with minor amounts of unsaturated compounds which are copolymerizable therewith in aqueous emulsion, such as styrene, alpha. methylstyrene, vinyltoluene, chlorostyrene, etc. In this case the products of the polymerization are high molecular weight linear polymers and copolymers'which are rubbery in character and may be called synthetic rubber. Although, as can be readily deducedfrom the'foregoing, there-is a host of'postan, employed will vary, depending upon the sible reactants, the most readily and commercially available monomers at present are butadiene itself (1,3-butadiene) and styrene. .The invention will, therefore, be more particularly discussed and exemplified with reference to these typical reactants. With these specific monomers, it is usually preferred to use them together, in relative ratios of butadiene to styrene between :35'and :10 by weight. I

It is generally preferred that the emulsion be of an oil in water type, with the ratio of aqueous medium to monomeric material between about 0.5: 1 and about 2.75:1, in parts by weight. It is frequently desirable to include water-soluble components in the aqueous phase, particularly when the polymerization temperatures are below freezing. Inorganic salts and alcohols can be so used. Alcohols which are applicable, when operating at low temperatures, comprise watersoluble compounds of both the monohydric and polyhydric types, and include methylv alcohol, ethylene glycol, glycerine, erythritol, and the like. The amount of alcoholic ingredient used in a polymerization recipe must. be sufficient to prevent freezing of the aqueous phase and'gener'ally ranges from 20 to 80 parts per parts of monomers charged. In most cases the amount of water employed is .sufficient to make the total quantity of the alcohol-water mixture equal '150 to 200 parts. In cases where it is desired to use a larger quantity of the alcohol-water mixture, say around 250 parts, the amount of alcohol may be increased to as much as parts. It is preferred that the alcohol be such that it is substantially insoluble in the non-aqueous phase, and that 90 per cent, or more, of thealcohol present be in the aqueous phase. 'A high-boiling alcohol such as glycerine is difficult to recover from the resulting serumya low boiling alcohol such as methanol is easily removed and frequently preferred. Other aliphatic alcohols of higher boiling pointthan methanol, such as a propanol, are frequently less satisfactory. If the resulting latex tends to 'gel at low reaction temperatures, a larger proportion of aqueous phase should be used. In the practice of the invention suitable means will be necessary to establish and maintain an emulsion and to remove'reaction heat to maintain a desired reaction temperature. The polymerization canbe' conducted in batches, semicontinuously, or continuously;

The total pressure on the reactants is preferably at least as great as the total vapor pressureof the mixture, so that the initial reactants will be present in liquid phase. Usually 50 to .98 .per cent of the monomericmaterial is polymerized,

In preparing synthetic rubber by polymerizing conjugated dienes; by the process ofthis invention, it is usually desirable to use a polymerization modifying agent, as is usually true in other polymerizations to produce synthetic rubber. Preferred polymerization modifiers for use'in the process of the present invention are alkyl meror blends of mercaptans are also frequently'cone sidered desirable and in many cases are preferred to the pure compounds. The amount of mercapparticular compound or blend chosen, the operating temperature, the freezingpoint depressant employed, and the results desired. In general,

the greater modification is obtained when oper ating at low temperatures and therefore a smaller amount of mercaptan is added to yield a product of a given Mooney value, than is used at higher temperatures. In the case oftertiary mei'captans, such as tertiary C12 mercaptans, blends of tertiary C12, C14,. and C15 mercaptans, and the like, satisfactory modification is obtained with 0.05 to 0.3 part mercaptan per 100 parts monomers, but smaller or larger amounts may 7 be employed in some instances. In fact, amounts as large as 2.0 parts per 100 parts of monomers may be used. Thus, the amount of mercapta is adjusted to suit the case at hand.

One of the advantages of the polymerization recipes, as disclosed herein, is that they are applicable for use in the production of high solids latices, i. e., latices resulting from the use of a smaller amount of aqueous medium than is generally used in conventional polymerization procedures. For this type of operation the'ratio of aqueous phase'to monomeric material will generally be in the range from 0.511 to 1:1 and the extent of conversion will generally range from '70 per cent to substantially complete conversion.

Emulsifying agents which are applicable in these low temperature polymerizations are materials such as potassium laurate, potassium oleate; and the like, and salts of rosin acids,

either alone or in admixture with each other.

However, other emulsifying agents, such as monionicemulsifying agents, salts of alkyl aromatic sulfonic acids, salts of alkyl sulfates, and the like which will produce favorable results under the conditions of the reaction, can also be used in practicing the invention, either alone or-in admixture with soaps. The amount and kind of emulsifier used to obtain optimum results is somewhat dependent upon the relative amounts of monomeric material and aqueous phase, the reaction temperature, and the other ingredients of the polymerization mixture. Usually an amount between about 0.3 and 5 parts per 100 parts of monomeric material will be found to be suificient. I r

The pH of the aqueous phase may be varied over a rather wide range Without producing deleterious effects on the conversion rate or the properties of the polymer. In general the pH may be within the range from 9 to 12 and it may be advantageous to have a pH higherthan 12 in some instances. In most cases optimum results are obtained if the pH is or higher.

When carrying out polymerization reactions according to the process of this invention, it is frequently considered desirable to include an electrolyte in the system, such as potassium chloride, trisodium phosphate, or other salt which will not produce deleterious eiiects. One function of an electrolyte is to increase the fluidity of the latex.- Generally the amount of such salt will not exceed one part per 100 parts of monomers.

We generally prefer to conduct the emulsion polymerization, as discussed herein, at low polymerization temperatures, i. e. from about C. to well below the freezing point of water, such as C. or lower. However, temperatures as highas 60 C. or even higher may be employed if desired. a

Advantages of this invention are illustrated by the following examples. The reactants, and their proportions, and the other specific ingredients of the recipes are presented as being typical tion unduly.

8 v Example I A diethylenetriamine-hydrazine composition was employed as the reductant, or activator, in the copolymerization of butadiene with styrene at 5 C. using the following recipe:

Parts by weight Butadiene 70 Styrene 30 Water, total. l Fatty acid soap, K salt 1 5 (pH of soap solution) 11.0 Mercaptan blend 0.1 Potassium chloride 0.4. 'I ert-butylisopropylbenzene hydroper- V v oxide 30.408 Activator composition:

Diethylenetriamine 0.5. Hydrazine 5 0.17

1 Potassium Oflice Rubber Reserve Soap.

.A blend of tertiary C C14, and C aliphatic mcrcaptans 111 a ratio of 3: 1: 1 parts by weight. f 1.96 millimols.

4 4.85 millimols.

5 5.3 millimols.

A mixture of the emulsifying agent, water, and potassium chloride was prepared and potassium hydroxide added to adjust the pH to 11. A solution of the hydroperoxide and mercaptan in styrene was then introduced followed by the butadiene. The reactor was pressured to '30 pounds per square inch gauge with nitrogen and the temperature adjusted to 5 C. The activator composition dissolved in 10 parts water was then charged to the reactor. Polymerization was effected in the conventional manner while the temperature was held at 5 C. A control run was made using 0.5 parts diethylenetriamine as the activator. The following results were obtained:

Conversion,

percent: Hours- Activator Diethylenetriaminc-hydrazine 24 46 "74 Diethyleuetriaminc ll 20 .47 00 Example II v Butadiene and styrene were copolymerized at -20 C. using the following recipe:

v Parts by weight Butadiene 70 Styrene 30 Water 187.5 Methanol 62.5 Potassium oleate 5 (pl-I of soap solution) 11.7 Mercaptan blend 1 0.25 Activator composition:

Tetraethylenepentamine 0.378

Hydrazine 3 0.2 Tert. butylisopropylbenzene hydropertetraethylenepentamine' The following results were obtained: I

Conversion percent: Activator Hours Tetraethylenepentamine-hydrazine v12 18 62 Tetraethylenepentamine 8 13 45 Example III The recipe of Example I was followed for carrying out a series of polymerizations at C. except that 0.208 part tert.-butylisopropylbenzene hydroperoxide was used insteadof 0.408 part. Variable amounts of diethylenetriamine and diethylenetriamine-hydrazine compositions were employed as activators. The-following results were obtained: r

The following example illustrates the slow polymerization rate which results when hydrazine alone is used as a reductant. The following recipe was used:

Parts by weight Butadiene '70 Styrene 30 Water 180 Emulsifier (K-SF flakes) 5 KCl 0.4 Mercaptan Blend 1 0.1

Tert. butylisopropylbenzene hydroper- Oxide Hydrazine (added as hydrazine hydrate) l AsinExample I.

1 2.0 millimols.

3 4.0 millimols.

At a polymerization temperature of 5 C. a conversion of 16 per cent was obtained in 24 hours.

As will be evident to those skilled in the art, various modifications of this invention can be made, or followed, in the light of the foregoing disclosure and discussion, without departing from the spirit or scope of the disclosure or from the scope of the claims.

We claim:

1. A process for the production of synthetic rubber, which comprises polymerizing a monomeric material comprising a major portion of 1,3-butadiene and a minor portion of styrene while dispersed in the presence of an emulsifying agent in an aqueous medium having a pH between 9 and 12 at a polymerization temperature between 30 and 40 C. in the presence of a polymerization catalyst composition comprising 0.1 to millimols of a monohydroperoxide of tert.- butylisopropylbenzene and 0.02 to 5 parts by weight of diethylenetriamine and hydrazine in an amount such that the mol ratio of hydrazine to diethyle'netriamine'is 0.3:1to 5:1, said amounts being per parts by weight of said monomeric material.

2. A process for the production of synthetic rubber, which. comprises polymerizing a monomeric materialcomprising a major portion of a conjugated diene having four to six inclusive carbon atoms per molecule while dispersed in the presence of an emulsifying ogent in an aqueous medium having a pH'between 9 and l2at a polymerization temperatiirebetween 30 and -40 C. in the. presence of a polymerization catalyst composition comprising 0.1 to 10 millimols of a mono- 'hydroperoxide of tert.-butylisopropylbenzene and 0.02 to 5 parts by weight of diethylenetriamine and hydrazine in an amount such that the mol ratio of hydrazine to diethylenetriamine is 0.311 to 5: 1, said amounts beingflper 100 parts by weight of said monomeric material.

iwhile dispersed in the presence of an emulsifying agent in an aqueous medium having a pH between 9 and 12 ata polymerization temperature between 30 and 40 C. in the presence of a polymerization catalyst composition comprising 0.1 to 10 millimols of an organic peroxide which is present in said monomeric material in a greater concentration than in said aqueous medium and 0.02 to 5 parts by weight of an ethylenepolyamine having not more than eight ethylene groups and hydrazine with a mol ratio of said ethylenepoly- 81111116130 hydrazinebetween 1:0.3 and 1:5, said amounts being per1'00 parts by weight of said monomeric material.

4. A process for the polymerization of a monomeric material comprising an organic compound having an active CH2=C group and polymerizable while dispersed in an aqueou medium, which comprises polymerizing said monomeric material while dispersed in the presence of an emulsifying agent in an aqueous medium having a pH between 9 and 12 at a polymerization temperature between 30 and 40 C. in the presence of a polymerization catalyst composition comprising 0.1 to 10 millimols of a monohydroperoxide of tert-butylisopropylbenzene and 0.02 to 5 parts by weight of diethylenetriamine and hydrazine in an amount such that the mol ratio of hydrazine to diethylenetriamine is 0.3:1 to 5:1, said amounts being per 100 parts by Weight of said monomeric material.

5. A process for the polymerization of a monomeric material comprising an organic compound having an active CH2=C group and polymerizable while dispersed in an aqueous medium, which comprises polymerizing said monomeric material while dispersed in the presence of an emulsifying agent in an aqueous medium having a pH between 9 and 12 at a polymerization temperature between 30 and 40 C. in the presence of a polymerization catalyst composition comprising 0.1 to 10 millimols of an organic peroxide which is present in said monomeric material in a greater concentration than in said aqueous medium and 0.02 to 5 parts by weight of an ethylenepolyamine having not more than eight ethylene groups and hydrazine with a mol ratio of said ethylenepolyamine to hydrazine between 1:03 and 1:5, said amounts being per 100 parts by weight of said asoase'ee terial comprising a major amount-ofa conjugated diene'while dispersed in an aqueousmediuminthe presence of a polymerization catalyst-ate terial comprising an organic compoundha'ving an,

active CH2=C group: while dispersed in an aqueous medium in thepresence of a polymerization catalyst at'a polymerization temperature, the improvementwhich comprises using as said polymerization catalyst an oXidant-reductant combination comprising an organic peroxide as said oXida-nt'and a mixture'of an alkylenepolyamine and'hydrazine as said reductant.

8. A process for the production of synthetic rubben which comprises polymerizing a monomeric'material comprising a major portion of LS-butadieneand a minor portion of styrene whileidispersedinthepresence of an emulsifying agent in an aqueous'medium having apI-I between-9 "and 12 at a polymerization temperature between 30and40 C. in the presence of a polymerization catalyst composition comprising :1to lil millimols'of a monohydroperoxide of tert butylisopropylbenzene and 0L02 to parts by Weight of :tetr'aethylenepentamine and hydrazine in an amount such that the mol ratio of hydrazineJ.to tetraethylenepentamine is 0.321 to 5:1,

saidamountsrbeingper 100 parts by weight of said-monomericmaterial.

'93A prooes's for the'production of synthetic rubberywhich comprises polymerizing a monomeric material comprising a major portion of a conjugated diene having four to six inclusive carbon atoms per molecule while dispersed in the presence of an emulsifying agent in an aqueous medium having a pH between 9 and 12 at a polymerization temperature between and 40 C. in the presence of a polymerization catalyst composition comprising 0.1 to 10 millimols of a monohydroperoxide of tert-butylisopropylbenzene and 0.02 to 5 parts by weight of 'tetraethylenepentamine and hydrazine in an amount such'- that the mol ratio of hydrazine to tetraethylenepentamine is 0.321 to 5:1, said amounts being per parts by weight of said-monomeric material.

10. The process of claim-6 in which-said peroxide is an organic hydroperoxide-having from ten-to thirty carbon atoms per molecule and said polyamine compound is diethylenetriamine.

,11. The process of claim 6 in which said peroxide is an organic-'hydroperoxide having from ten'to thirty carbon atoms per molecule and said polyamine compound is tetraethylenepentamine.

WILLIAM B. REYNOLDS. JOHN E. WICKLATZ. THOLIAS J. KENNEDY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,429,060 Hoover et al. Oct. 14, 1947 2,436,926 Jacobson Mar. 2, 1948 OTHER REFERENCES Whitby et aL, Rubber Age, vol. 65, page 545, August 1949. 

1. A PROCESS FOR THE PRODUCTION OF SYNTHETIC RUBBER, WHICH COMPRISES POLYMERIZING A MONOMERIC MATERIAL COMPRISING A MAJOR PORTION OF 1,3-BUTADIENE AND A MINOR PORTION OF STYRENE WHILE DISPERSED IN THE PRESENCE OF AN EMULSIFYING AGENT IN AN AQUEOUS MEDIUM HAVING A PH BETWEEN 9 AND 12 AT A POLYMERIZATION TEMERATURE BETWEEN 30 AND -40* C. IN THE PRESENCE OF A POLYMERIZATION CATALYST COMPOSITION COMPRISING 0.1 TO 10 MILLIMOLS OF A MONOHYDROPEROXIDE OF TERTBUTYLISOPROPYLBENZENE AND 0.02 TO 5 PARTS BY WEIGHT OF DIETHYLENETRIAMINE AND HYDRAZINE IN AN AMOUNT SUCH THAT THE MOLE RATIO OF HYDRAZINE TO DIETHYLENETRAIMINE IS 0.3:1 TO 5:1, SAID AMOUNTS BEING PER 100 PARTS BY WEIGHT OF SAID MONOMERIC MATERIAL. 